In the manufacture of propellants and fuels, it was generally known to utilize borates or borohydride salts, as disclosed in U.S. Pat. No. 3,563,818 to Miller et al. and U.S. Pat. No. 3,564,561 to Carvalho et al. Certain metaborate esters which were formed from acyclic polyols and metaboric acid were found useful in liquid fuels and lubricants as is disclosed in U.S. Pat. No. 2,866,811 to Irish et al. It was also known to utilize triethanolamines in propellants and fuels as disclosed in U.S. Pat. No. 3,790,416 to Dehm; U.S. Pat. No. 3,807,973 to Iwama et al.; and U.S. Pat. No. 4,154,633 to Pierce.
It was desired in the castable solid propellant and fuel art to incorporate powdered amorphous boron with a binder pre-polymer having hydroxyl-functional groups. This attempted incorporation was only limitedly successful because it was found that there is a reaction between the boron surface impurities, namely, boric acid and boron oxide, and hydroxyl-functionally active pre-polymers, so as to form borates. The multi-functional pre-polymer reaction caused cross-linking with the boron which resulted in a non-flowing, noncastable, rubbery mass.
It is therefore a principal object of the present invention to provide a method for rendering the amorphous boron unreactive to the hydroxyl-functional pre-polymers so as to provide a castable substance for solid propellants and fuels.